A harmless button in Twitter’s mobile application bears a resemblance to Path’s contact list uploading controversy, ZDNet reports. Twitter has admitted it stores user contact details — including phone numbers and eMail addresses — for an 18-month retention period when the service’s “Find friends” feature is used. New and existing Twitter followers alike can upload their contacts list and address books from a variety of platforms to see if any of their contacts match up to a Twitter registered account. Once users access the feature from one of its smartphone applications, it uploads the data and is subsequently stored for 18 months…